This invention generally relates to a fuel stabilization system for an energy conversion device, and more particularly to a fuel stabilization system including several fuel deoxygenators for removing dissolved oxygen from a fuel.
Hydrocarbon fuels typically include some amount of dissolved oxygen due to exposure to air during transport or storage. Dissolved oxygen within the fuel limits the temperature to which the fuel may be heated due to the formation of insoluble products referred to as “coke”. The formation of coke deposits is dependent on the amount of dissolved oxygen present within the fuel. Reducing the amount of dissolved oxygen within the fuel decreases the rate of coke deposition and increases the maximum sustainable temperature of the fuel.
U.S. Pat. Nos. 6,315,815, and 6,709,432 assigned to Applicant, discloses devices for removing dissolved oxygen using a selective gas-permeable membrane disposed within the fuel system. As fuel passes along the permeable membrane, oxygen molecules in the fuel diffuse out of the fuel across the gas-permeable membrane. An oxygen partial pressure differential across the permeable membrane drives oxygen from the fuel, which is unaffected and passes over the membrane.
The more dissolved oxygen that can be removed from the fuel, the greater the fuel temperature before coke deposits form, thereby increasing the practical temperatures to which fuel can be heated prior for combustion to improve operating efficiencies. Disadvantageously, the size of a fuel deoxygenator increases proportionably with the requirements for removing oxygen. An increase in oxygen removal from 90% to 99% may require nearly a doubling of deoxygenator size. Further, as operational requirements change, so may the required oxygen removal rate. A single fuel deoxygenator may not adjust readily or be scalable to accommodate variations in oxygen removal requirements.
Accordingly, it is desirable to develop a fuel stabilization system that removes dissolved oxygen to allow increased fuel temperatures, and that is scaleable to accommodate changing oxygen removal requirements.